Automobile jack



Patented Oct. 9, 1951 m 'omcs AUTOMOBILE JAoK Russell H McCarroll,Dearborn, l vlich}, assignor to Ford MotofCoinpany, Dearborn, Mich," a

corporation of Delaware Application April 25, 1946, Serial No. 664,817

This invention relates to automobile jacks; and,

more particularly, to manually operated jacks of the friction type.

V The object of my invention is to provide a sup-- port rod for afriction type jack comprising a steel shaft having a noncorrosive metalsheath or'casing autogenously attached to its working surface, thissheath being hard enough to resist indentation under normal use andhighly resistant to surface deterioration.

The shaft of this type of jack is particularly prone to deteriorationthrough rusting, since any the common lubricants adversely affect thefrictional n agement. Further, in normal use,' the jack may be storedfor. months at a time without beingoperated in the tool compartment ofthe vehicle where it willbe subjected to moisture, increasing the rateof deterioration.

A further object of this invention is to provide;

an improved type of automobile jack which affords a definite supportwithout the hazards of slippage or accidental release. A second objectis to provide a jack'whioh will be positive and;

smooth in operation, and which will not stick,

jam, or slip, even after the long periods ofdisuse common with thesedevices.

The improvements with which rangement, construction, and combinationofthevarious parts of my improved device as described in thisspecification, claimed in my claims, and illustrated in the accompanyingdrawings, in which:

Figure 1 ,is a full-sized elevation of the jack in lowered positionwith'the central portion-of the housing cut away.

Figure 2 is a sectional view on an enlarged scale, takenas indicated bythe lines 2--2 of Fi ure 1.

"this invention. is concerned,- are directed to the conventional otallymounted on the pin 15. The inner end' Figure 3 is a sectionalview takenon the lines I 3-3 of Figure 2. 1

'Referring now to Figure 1, the jack consists of three basic units: theshaft 2, foot plate 3" 7 into which the shaft 2 is removably insertedand the housing 4, which is substantially cylindrical in shapecontaining the lifting and locking mechanism of the jack and arrangedfor reciprocatory travel onv the shaft 2. I

g The housing 1' has, at one side, two spaced ears" I5 between 'whichthelifting lever 6 is pivofthe lever is forked and its two extensions l8and 22 engage the lifting dogs 5, slidably mounted on the shaft 2 as thelever is moved upwardlylto lift the housing) or downwardly (to reset thelifting dogs) respectively. The

dogs 5 are in theform of thin metal discs having a central hole with adiameter slightly larger than that of. the shaft 2 upon which theyarestrung and are normally urged into position, normal to the shaft,against the shoulder 25 by the spring 23.

The housing [also encloses the locking dogs 8. which are similar tolifting dogs 5, except having a fulcrum extension l0 seated in the fulcrum recess II of the housing 4 and a release.

extension I 2 projecting through the slot 2| which is a'continuation ofthe opening between the ears l6 through which the lever Boperates. The1ock ing v dogs 8 are normally urged to the cocked position shown withthe diametrally opposite edges ofthe holes 20 engaging the shaft 2 (seeFigure 2) by the spring 11 seated on the shoulder- 25. The, upper endof'ithe housing 4 'carries a rotatable collar 9 having a notch inwhichmay be s'eatedthe bumper bar or bumper bracket l9 of" the vehicle to be,lifted. 7

This structure is, it will be recognized, all

ventional and is set forth briefly, merely to assist in' anunderstandingof the invention. The operation of the-device is also conventional.Asethe lever B (usually operated through anextension;

lever inserted inthe socketf l'l) begins to move counterclockwise, theextension I8 engages the lifting dogs 5 on one side-cocking them intoing upwardly along the shaft 2, which slides freely through the. lockingdogs 8. When the limit of counterclockwise rotation is reached and thelever 6 begins its return to the original position, the

initial resultant return movement of the housing 4 cocks the lockingdogs 8 into engagement with shaft 2 preventing further downwardmovement:

of the housing, and the extension 22 restores attained. The jack islowered by inserting a lever in the slot 2| abovethe'extensionsl2 andforcing: them downwardly, restoring the locking dogs 8 to horizontalposition and permitting the housing to 'slide' downwardly on the shaft2. As noted above, thisis. the usual mode of operation ofv jacks of thisgeneral type,

relatively noncorrosive metal, such as copperhor cadmium. Neither hasbeen satisfactory, because the fundamental requirements for proper operaphysical properties fully catalogued. For the present purpose, any ofthe harder brasses or bronzes are sufliciently noncorrosive. Sincehardness of the coating in the drawn rod is probably the primeconsideration, attention is directed to the manganese bronzes (e. g. Cu68.5%, Al 4%, Zn 22%, Mn 3% and Fe 215%) aluminum bronzes (e. g. Cu 90%and A1 silicon bronzes (e. g.

Cu. 81.5%, Zn 4% and Si 4.5%) or the standard 10' Phosphor bronzes.While a Brinell hardness in excess of 200 would be most desirable, itmay be somewhat lower and the softer alloys may also tion have beenoverlooked. If the'jackisto operate smoothly and easily, the mainreliance in lifting and locking must be put onthe frictionalen gagementbetween the dogs and shaft rather than on actual physical interlocking,due to surface ole":

formation. It is true that if the shaft were quite soft; and the dogsrelatively harder, the jack might be operated purelythrough successivedeformation rather than-frictional engagement at least for a time. Butthis results in pronounced corrugation of the shaft and it is soon"foundthat the dogs will not engageand disengage smoothly and-much moreto the'-point'the cor rugations will shear off under load; releasingthejack when least expected; Actually; there is boundto be at least atransitory :deformation in the area of contact between the dog andshaft; but b keeping the surface layer hard enough; permanentdeformation can be avoided; Such hardness could not, however,be'obtained' in'the plated layers of the ordinarilyavailable'metalsheretofore used, since both copper and cadmium are very soft when soapplied and cannot be hard ened perceptibly by available heattreatments; Even more disadvantageous was the tendency of the platedcoat to strip off in use. While the bond between the plated layer andthe base metal may be sufliciently' strong; for many purposes; herethere a" constant succession of forces'of con"? siderable magnitudeimposed on relatively" small areas resulting intransitory, ifnotpermanent relative deformationof the plated layer and the base. Undersuch service, the" bond soon fails and the entire outer layer stripsaway; H 'Itherefore sought a' nonoorrosi've covering for the shaft whichwould be-ve ry-hard, have as high" a" coefficient of friction" aspossible; and would have a bond with the shaftwhich would not fail underload short of failure of the: layer itself. This combination was foundto exist uniquely in a shaft prepared by fusing a layer of acopper-basealloy having high hardness characteristics'to the outer surface of asteelingot and subsequently drawing this composite structure down-w a;barof the desired diameter for the shaft in which the thickness of thealloy layeifwas about 0.010 inch or less. This process is; of course;currently used under several trade names to fabricate cop per-clad steelarticles, such as bus bars-yelec'trical cables, and the like. y p

The advantage of such a; structure in this combination will beat onceapparent. The" bond be tween the casing and shaft is very strong afterthe initial fusing or welding and isnot deteriorated in the'drawingsteps. Almost any desired copper-base alloy may be used: to obtain ahard cas ing (which is not, of course; practicable with plat ingmethods) and this physical characterist'ic is increased by the workingincident'to the drawin operation. I do not undertake tof specify anyparticular alloy as most suitable, sincetlie list of copper-base alloysis readily available and the" Y) a copperbase alloyless' than 0.01"thick having further means of preventing surface defor- 'mation' is'byreducin the unit loads existing between the f'rictionally engagingmembers.

This may best be done by increasing the number of individual discs,making up each of the locking and lifting do gsfour being shown in usein the drawings. This is very effective in reducing deformation andprovides an additional safety factor in use. 5 V

Somechanges ma be madein' the arrangement, construction, and.combination of the various parts of the improved device withoutdepartingfrom the spirit of the invention an'd it is intention to coverby the claims suchchanges as may be reasonably included in the scopethereof a V I claim asmy invention l 1. In combination, in'afriction-type vehicle.- li'fting jack, a housing-, a centralsu'ppo'r-ting shaft a thickness less than 0.01f andaiBrinell-hardriessin excess of 200.

2. In combination; ina friction typ vehicle" lifting jack, a housing; acntralsupportingshaft having a steel core extending through saidhousing, said steel core having secured thereto a rela-' tively hardexterior layer of non-corrosive metal; ayliftihgine'chanism, and alocking mechanism successively and selectively frictionally engagingsaid exterior layer, said exterior layer comprising ahardness inexcessof 200Brir'1ll and saidm'ec'h anisms each comprise apluralityofdisks su'r:

u se d efi- In n ign; a iq g i txpyehi l l f ing jack, a housing; acentral sup orting shaft having a steel" core-extending throughsaidihous' f' me; said St el 0 16 hav n secur h r 't re. tively hardexterior layer of non-corrosive rne't a lifting mechanism, and a lockingmechanism successively and selectively frictionally engaging saidexteriorlayer, sa'i'd' exterior layer being'acop-f per base alloy havinga Brine'll hardness in excesso'f200: w; r l. K RUSSELL H MCCARRGLE.

REFERENCES emu The following references are of record in the file ofthis patents UNITED STATES PATENTS

